Lubricating oil



Patented June 18, 1940 UNITED STATES PATENT OFFICE- nunn carmo' on.

Robert Charles Cantelo, Hammond, Ind, assignor to Sinclair RefiningCompany, New York, I N. Y, a corporation o! Maine No Drawing.Application January 24, 1088,

I Serial No. 186,582

4 Claims.

. the physical characteristics and lubricatin properties of the oils.The invention includes a novel addition agent having the eflect 01'improving the physical characteristics and lubricating properties ofpetroleum hydrocarbon oils and also includes an improved compoundedpetroleum hydrocarbon oil containing the novel addition agent of theinvention.

Oi the numerous prerequisites for a petroleum lubricating, oilsatisfactory for use in internal combustion engines, three are of majorimportance. The oil must be stable duringstorage, handling and use sothat deterioration. of the physical properties of the oil, particularlyduring useywill not occur. Secondly the oil should be substantiallynon-corrosive toward the bearings used in internal combustion engines sothat the wear and loss or weight of these bearings is reduced to aminimum. Furthermore, the oil pronounced and results in serious changesin the composition and characteristics of the oil when the oil is usedfor lubricating internal combustion engines such as are employed inmodern automobiles and aeroplanes where the oil is in contact withrapidly moving and highly heated engine parts. Such deterioration oflubricating oils is characterized, in oneaspect, by the formation ofheavy sludge which tends to collect in' the oil pump and oil lines ofthe engine and eventually to clog them to such an exf tent as to preventor greatlyimpair the eflicient lubrication of the engine. Thisdeterioration the modern internal combustion engines.

lubricating oil thereby subjecting the engine to a correspondinglyincreased load.

The corrosive characteristics of these lubricating oils are ofparticular importance in view of the present'trend toward thesubstitution of .bearing metals such as cadmium-silver and copperbronzealloys for the previously used babbitt metal. Babbitt bearings-aregenerally highly resistant to corrosion; the new types of bearing al-IOYS are more susceptible to CON-081011.. Any 001- rosive action oflubricating oils increases marked- 1y with increasing temperatures and,consequently, presents a very serious problem where, as in moderninternal combustion engines, the lubricating oil temperatures frequentlyare as milligram of a babbitt bearing in 24 hours, under 2Q similaroperating conditions effected a lossof' 2012 milligrams of acadmium-silver bearing substituted for that babbitt bearing in the sameperiod.

high as 200-350 F. during normal operation.

The film strength of these lubricating oils is 26 of particularimportance in view of the high pressures encountered between movingparts of -A high film strength insures the complete protection of movingparts by insuring the presence 0! a film of the lubricating 011 betweenthese moving parts. A breakdown of such a film due 1 to inferior filmstrength results in the scoring and undue wearof adjacent moving parts.

Special methods have been devised for measuring the above-mentionedprerequisites of lubricating oils under various conditions. v

A generally satisfactory method of measuring the stability oflubricating oils in terms of the rate oi sludgeformation has beendescribed in the Society of Automotive Engineers Journal,

vol. 34, No.5, page l72. According to this method'the time is determinedin which 10 milligrams of sludge are formed in 10' grams of the oilmaintained ata definite temperature while air is bubbled through the oilat a specified rate. This time, expressed in hours, is designatedsludging time and-is a measure'of the rate of m further causesan-increase in the'viscosity oi the sludge-formation in that particularoil under 59 the particular conditions of the test. The term sludgingtime as used hereinafter refers to the above-determined measure of therate of sludgeformation and is a relative measure of the stability oflubricating oils under conditions of storage or use.

A generally satisfactory method for determining the corrosive action oflubricating oils may be carried out with the Sinclair bearing corrosiontest machine. In determining the corrosive properties of lubricatingoils referred to herein I have used this test machine. This test machinecomprises a test chamber the cover portion of which comprises a leadalloy bath which may be heated by electrical resistance units. A shaftextends through the interior of in the test chamber on one side wallthereof above the level of oil within the chamber, and each test bearingis attached to the removable bar at a point opposite each set of crossarms mounted on the shaft. As the shaft is rotated a stream of the testoil is directed by each of the cross arms against each of thetest-bearings. Means are further provided for continuously passing airthrough the test chamber. In addition to the temperature regulationprovided by the lead alloy bath in the cover portion of the testchamber, the chamber is partially submerged in a heated oil bath and thetemperature of the test oil thus controlled.

The corrosion test is divided into two stages. In the first stage thetest is conducted on a set of weighed bearings for a period of twelvehours.

The test oil is maintained at 350 F., the lead althese bearings areweighed, and the loss in weight of each bearing in each stage isreported in milligrams. A loss of bearing metal through corrosion, asdetermined by the above test, substantially in excess of 100 milligramsin either stage of the test indicates that the particular lubricatingoil is excessively corrosive with respect to bearings of the typetested. Although it is desirable to reduce the corrosive action .of theoil to a minimum it is usually suflicient for practical purposes thatsuch action be so reduced as to effect a loss of not substantiallygreater than 100 milligrams in either stage of the test.

A representative comparison of the film strength of different samples oflubricating oil may be obtained by the use of the Faville-Le- Valleytest machine. This test machine measures the point, expressed inpoundspressure applied in the machine, at which a film of lubricatingoil breaks down between two metal parts, one part moving with respect tothe other. Although this machine does not necessarily determine. theactual film strength of a particular sample of lubricating oil, it hasbeen found to offer a useful means of comparing the relative filmstrength of different samples of lubricating oils.

I have discovered that the physical characteristics and lubricatingproperties of petroleum lubricating oils may be greatly improved byincorporating in such oils a small proportion of heptadecyl phenylthioketone (CI'IH35) CS- (CeHa) The incorporation in a lubricating oilof a small proportion of heptadecyl phenyl thioketone, hereinafterreferred to as the addition agent, improves the stability of the oil asshown by an increase in the sludging time, decreases the corrosiveeffect of the oil on internal combustion engine bearings and the like,and also increases the film strength of the oil as indicated by anincrease in the breakdown point of the oil. I have foundthat, ingeneral, these improvements in the general characteristics andlubricating properties of the oil are realized by the incorporation inthe oils of between 0.1% and 3.0% of the addition agent by weight on theoil.

The heptadecyl phenyl thioketone used in accordance with my inventionmay be prepared, for example, by first producing heptadecyl phenylketone dichloride from heptadecyl phenyl ketone. and subsequentlyreacting the heptadecyl phenyl ketone dichloride with sodiumhydrosulphide.

In preparing the heptadecyl phenyl thioketone referred to further hereinin examples of my invention, 150 parts (by weight) of stearyl chloride(CnHasCOCl), 33 parts of benzene and about 250 parts of carbonbisulphide were placed in a reaction vessel fitted with a refluxcondenser. After the mixture was cooled by means of an ice bathsurrounding the reaction vessel, 65 parts of anhydrous aluminum chloridewere added to the reaction mixture. Hydrogen chloride was producedduring the reaction and after the rate of evolution of hydrogen chloridehad diminished the ice bath was removed from around the reaction vessel.The reaction mixture was allowed to warm up to room temperature with afurther evolution of hydrogen chloride. The mix- I ture was then heatedto a reflux temperature and gentle refluxing was continued for a periodof several hours. The reaction mixture was subsequently cooled andpoured into about 500 parts of a mixture of ice and water after whichabout 240 parts of 38% hydrochloric acid were added to decompose thesludge-like material in the reaction mixture. The acid solution was thendrawn off and an additional 625 parts of carbon bisulphide was added tothe remaining solution of heptadecyl phenyl ketone. After successivewashings with water, the carbon bisulphide was removed from thissolution by distillation and the residue comprised about 140 parts ofheptadecyl phenyl ketone.

In converting this ketone to the corresponding thioketone, 58 parts ofthe heptadecyl phenyl ketone and parts of phosphorus pentachloride wereheated at 300 F. for a period of two hours. The phosphorus oxychloridethus formedwas removed from the mixture by vacuum distillation.

for providing an inert atmosphere within the re- 76 action vessel. Analcoholic solution oi sodium hydrosulphide was then prepared bydissolving 6.3 parts of metallic sodium in about 160 parts of absolutealcohol and by then saturating this solution with hydrogensulphide gas.This solution of sodium hydrosulphide was then added slowly to theheptadecyl phenyl ketone dichloride while stirring the reaction mixturevigorously and while passing carbon dioxide through the reaction vesselto maintain an inert atmosphere. A low temperature was maintained withinthe reaction mixture by means of an ice bath surrounding the reactionvessel. After all of. the sodium hydrosulphide solution had been added,the mixture was allowed to stand for a period of about one hour at theend of which period water was added to the mixture. Heptadecyl phenylthioketone was extracted from this mixture by means of benzene whereuponthe benzene solution was dried over anhydrous calcium chloride, thesolution decanted, and the benzene removed from the extract bydistillation. 54.9 parts were left as a residue in the distillationoperation, and this residue comprises the heptadecyl phenyl thioketonewhich I use in the practice of my invention. An analysis of the sulphurcontent of this residue indicated that the compound contained about3.82% sulphur. Inasmuch as heptadecyl phenyl thioketone theoreticallycontains 8.8% sulphur, it appears that the product which I use inaccordance with my invention and which is referred to herein asheptadecyl phenyl thioketone comprises about 43% heptadecyl phenylthioketone and the remainder unconverted heptadecyl phenyl ketone. Thismixture can not easily; be separated by fractional distillation or theli e. stantially pure heptadecyl phenyl thioketone alone may be usedwith advantage or this pure compound may be blended with heptadecylphenyl ketone to produce a satisfactory addition agent. I have found,however, that the mixture of heptadecyl thioketone and heptadecyl phenylketone prepared as described above may be used with particular advantagein the practice of my invention.

A more complete understanding of my invention may be had uponconsideration of the following examples which have been reproduced intabular form. It must be understood that these examples should in no waybe construed as a limitation of the scope of my invention inasmuch asthese examples are given merely to illustrate the improved resultsobtained by incorporating in lubricating oils a. small proportion ofheptadecyl phenyl thioketone. I

The examples referred to above are summarized in Table I. There is shownin this table the efiect of 1.0% by weight of the addition agent uponthe stability, corrosiveness, and the film strength of a Pennsylvaniamotor oil. This oil, before the incorporation therein of the additionagent, had a gravity of 28.2" API, a viscosity of 448 seconds Saybolt atF., a viscosity of 62.0 seconds Saybolt at 210 F., a viscosity index of103.5, and a pour point of -5 F. The stability of the uncompounded oiland of the blended oil is indicated by the sludging time expressed inhours. The corrosiveness of the samples is shown by the loss of weight,expressed in of copper-lead and cadmium-silver bearings of an internalcombustion engine. The film strength of the oil samples is indicated bythe breakdown point, expressed in pounds. of these samples as It shouldbe noted, however, that subdetermined by the Fa'ville-LeVally testmachine.

Table I Percent addition agent 0 1. 0

Sludging time, hours A, 60 72 Bearing corrosion; lst stage C'u-Pb loss,mgr 637 '55 Cd-Ag loss, mgr 1561 45 2nd stage- Cu-Pb loss, mgr i084Cd-Ag loss, mgr i237 3i Breakdown, pounds. 750 2250 The results of TableI show that the stability and film strength of this particularPennsylvania motor oil may be substantially increased and thecorrosiveness of the oil may be markedly reduced by the incorporationtherein of 1.0% by weight heptadecyl phenyl thioketone. time, that is.the time required for the formation of 10 milligrams of sludge per 10grams of oil, is increased from 60 hours for the blank oil to 72 hoursfor the blended oil. The corrosive action of the blank oil is shown tobe substantially eliminated by the incorporation therein of 1.0% byweight of the addition agent. The breakdown point, which is a measure ofthe film strength of the oil, is increased from 750 lbs. for the blankoil to 2250 lbs. for the blended oil containing 1.0% by weight of theaddition agent.

It will be seen from the foregoing examples that salient improvementsmay be made in the physical characteristics and lubricating propertiesof petroleum lubricating oils by the incorporation therein of a smallproportion of heptadecyl phenyl thioketone. The stability of the oilsmay thus be increased, the corrosive nature of the oils diminished andthe film strength of these lubricants markedly improved. Although theheptadecyl phenyl thioketone has been illustrated herein with respect toits eilecton a particular Pennsylvania motor oil, it should be notedthat this addition agent may be used with advantage with otherlubricating oils when it is desired to increase the stability, decreasethe corrosive nature, or increase the film strength of these other oils,or eifect a combination of these results. Thus, for example, when theaddition agent of my invention is incorporated in a substantiallynoncorrosive lubricating oil the stability and film strength of the oilwill be improved although no noticeable improvement may be observed inthe foregoing illustrations may be used advantageously with other oils.As little as 0.1% by weight of the addition agent may be sufiicient inmany instances to produce the desired effect. The optimum proportion ofthe addition agent which may be used in each particular instance may bereadily ascertained by the simple tests hereinbefore described, thisoptimum proportion depending not only upon the characteristics of theoils but also upon the property or properties of the oil which it isdesired to improve.

Although the use of the addition agent of my invention has beendescribed above as the only substance incorporated in the oil, it shouldbe noted that this addition agent may be used with advantage incompounded petroleum oils containing other addition agents in which casethe addition agent or my invention may supplement The sludging orenhance the effect of the other addition agents 'in the compounded oils.The addition agent of my invention may be used furthermore to correct orto overcome some deleterious eflect upon a lubricating oil caused by thepresence of another addition agent incorporated in the oil for anotherpurpose.

I claim:

1. An improved lubricating oil which comprises a petroleum lubricatingoil containing a. small proportion of heptadecyl phenyl thioketone.

2. An improved lubricating oil which comprises a petroleum lubricatingoil containing between about 0.5% and 1.0% by weight of heptadecylphenyl thioketone.

3. An improved lubricating oil which comprises a petroleum lubricating011 containing a small proportion of a mixture of heptadecyl phenylthioketone and heptadecyl phenyl ketone.

4. An improved lubricating oil which comprises a petroleum lubricatingoil containing between about 0.5% and 1.0% by weight of a mixture ofabout 43% heptadecyl phenyl thloketone and 10' about 57% heptadecylphenyl ketone.

ROBERT cmmms clwmno.

' CERTIFICATE OF CORRECTION.

Patent No.'2,20h,661. June 1 8, 1914.0.

' ROBERT CHARLES CANI'ELO.

It is hereby certified that error appears inthe printed apecifioationvof the above mmbered. patent requiring correction as follows: Page 5first column, line l|.5, before-"thioketozie" insert --pheny1--;ant1that the said Letters Patentshould be read with this oorrection thereinthat the same may conform to the record. of the case in the PotentOffice.

Signed 'endfsealed this. 50th day oi July, A. D. 1914.0

Henry Arsdale (Sea1) Acting Commissioner of Patents.

